Recycling may be a key component of modern waste reduction and may help sustain the environment for future generations. Recycling efforts can prevent waste of potentially useful materials, reduce the consumption of raw materials, reduce energy usage, and the like. According to estimates from the automotive industry, 95% of all motor vehicles removed from service are processed for recycling. This equates to approximately 9 to 10 million vehicles each year in the US. In the recycling process, cars may be dismantled and stripped of reusable parts. The stripped cars may be sent to auto shredding operations where automobile shredders such as hammermills crush them into smaller pieces. Metal chunks are recovered and sold to metal scrap and nonferrous metal processing industries. On average 75% of a vehicle by weight is recycled. The remaining 25% of the vehicle is commonly landfilled. Major household appliances can also be recycled but create residues that cannot be recycled. The remaining material from the recycling of automobiles, trucks, buses and common household appliances such as washers, dryers and refrigerators and the like is called automobile shredder residue also known as auto fluff, or auto shredder fluff. It is estimated that 2 billion pounds of automobile shredder residue are generated annually.
Realistically, automobile shredder residue contains recyclable components such as plastics and metals mixed in with trash and magnetic fuzz. It is desirable to provide a system that can further process automobile shredder residue to separate the recyclable components in a form that can be used for recycling. Previous particle classification systems such as discussed in U.S. Pat. No. 3,972,808 to Manley and U.S. Pat. No. 4,312,748 to Rozmus, both hereby incorporated by reference herein, would not work with automobile shredder residue among other reasons. Manley was designed for mineral and mine run materials and Rozmus was designed for powders and metal powders. Unlike automobile shredder residue, minerals, mine run minerals, and powders may be somewhat homogenous pre-classification. Automobile shredder residue may be a seemingly homogenous substance but may actually have a lot of various materials and maybe somewhat heterogeneous containing different substances such as glass, fabric, metals, dirt, plastics, rubber, trash, and the like. Separation of automobile shredder residue is very different from minerals, mine run materials, and powders.
Other systems have been developed to recover recyclable components from automobile shredder residue. Such traditional systems include magnets, eddy current, air separation perhaps only as an air sensor puff, flotation, screening, sensor sorting, induction sensor sorting, and X-ray. However, these traditional systems still produce end products that contain recyclable components which end up as waste in a landfill. The traditional sorting systems for automobile shredder residue also provide recyclable products which may be unclean and even unusable perhaps making the recycling process less efficient. Therefore, there is a need for a system to enhance separation of recyclable materials from auto shredder residue to provide cleaner recyclable products and more recyclable products from what would otherwise be trashed.
Unlike past systems which may only afford incremental increases in the recovery of recyclable materials from auto shredder residue, the present invention utilizes techniques which were not previously considered to achieve impressive sorting results compared to the prior art.